Bending machine



Nov. 30, 1943.

O. BERG STROM BENDING MACHINE Filed Jan. 13, 1943 2 Sheets-Sheet lPatented Nov. 30, 1943 UNITED STATES PATENT OFFICE BENDING MACHINE OscarBergstrom, Evanston, 111., assignor to Orville R. Owens, Oollegeville,Pa.

4 Claims.

This invention which relates generally to bending machines is concernedparticularly with certain improvements by which to performsimultaneously two or more bends in a single board made of some suchmaterial as plywood, pressed board material, etc. Such a multiple bendis desired for certain products, e. g. reflectors for fluorescentlights.

The principal object of this invention is the provision of meansadaptable to existing machines by which boards may be given multiplebends, all uniform but varying widely in contour according to the formused. For this purpose I have devised a forming die, attachable to theusual bending roll, and itself complete with heating elements, adaptedto cooperate with a pair of female dies adjustable toward and from eachother, all the operating parts being properly shaped and co-related toproduce the desired.

bends. By my invention a machine is convertible from one which make asingle bend to one which may produce a plurality of bends of variouscontours and spacing.

The forming means attachable to existing machines by which multiplebends may be performed is simple, sturdy and strong. It is also readilyfitted in place or removed therefrom, as desired, and in operation maybe relied upon to produce dependably bends which will be uniform and inwhich imperfections and injury to the board will be lacking. Asuggestive embodiment of my invention will be hereinafter described indetail in conjunction with the accompanying drawings at each end of themachine, between which are extended a fixed male bending die in the formof a roll [5 and therebelow a table T vertically movable on the columns,the table mounting a pair of spaced female dies in the form of bendingbars l6 each adjustable toward and from the other to vary the distancetherebetween. The

table is centrally divided or slotted lengthwise to receive a pressureplate I! supported upon piston rods l8 each of which is upwardlyextended from a cylinder mechanism I9. In like manner the table issupported upon piston rods 2|] each extended upwardly from a cylindermechanism 2|. These several table operating cylinder mechanisms 2| maybe pneumatically interconnected with a source of pressure which isthereby equalized and made subject to control by an air reducing valve(not shown). So that the vertical table movements may be positivelyequalized, I have suspended from the table near each end of the machinea post 22 whereon is a rack bar 23 (see Fig. 5) each in mesh with a gear24 carried fast at opposite ends of a shaft 25 that is mounted to rotatewithin bearings 26. The cylinder mechanisms H! are also desirablyinterconnected. pneumatically with a source of pressure, and a commonautomatic valve control for the two sets of cylinder mechanisms I9 and2| may also be: provided whereby to assure timed operation thereof, thepressure bar being raised first to clamp and hold the work W against themale die, the table thereafter being raised to bring the female diesinto cooperative position so that the work is bent in consequence, andfinally the table and also the pressure plate being lowered to releasethe work at the conclusion of the bending operation.

The female dies, i. e., the bending bars iii, are supported upon rails30 which, together with the bars, may be shifted toward and from thelongitudinal center of the machine whereby to vary the spacingtherebetween. The connecting bolts 3| which are entered throughtransverse slots 32 in the table afford a convenient means of securingthe bending bars in a desired position of adjustment. Also bysubstituting other rails of greater or lesser height the female dies maybe brought closer to or further from the male die. The work W, such as aplywood sheet, a pressed board, etc., is placed across the two bendingbars, preferably upon an underlying spring steel shield 33, then therising pressure plate engages the shield from below to clamp the workagainst the male die, and iinally an upward movement of the tableadvances the bending bars against the shield which protests the workfrom frictional contact therewith while the work is bent upwardy inconformity with the contour of the male die. Where the machine is longand the male die is transversely small, there may be need ofintermediate bracing such as is provided by the several struts 34adjustably secured to blocks 35 at spaced intervals along the uppersurface of this die, these struts being connected to a common head 36which is supported at its ends upon columns 31 which extend upwardlyfrom the housings II.

The initial position of the Work before start of the bending operationis indicated in Fig. 3, whereas in Fig. 4 I have shown the work andmachine as at the conclusion of, this operation. To facilitateproduction of the desired bend in the work without injury thereto, themale die is provided interiorly with one or more electrical heatingelements 38 in connection with a source of energy, this element (orelements) extending lengthwise of the die, the heat thus delivered beingtransmitted through to the exterior of'the die for delivery to the workin the to-be-bent area thereof.

The machine thus far described has capacity.

for producing a single bend in each operation. Multiple bends requirethat the, work be shifted and that the operation be repeated. Not alsodoes this involve the time factor, but a correct positioning of the workfor each operation, if the bends areto be accurately located relative toeach other. With a View to adapting such a machine to the performanceof. multiple bends in a single operation I have devised an attach,- mentfor the male die, itself a male die different in form therefrom butsupplementary thereto, and yet complete for cooperation with the spacedbending bars which constitute the female dies. As shown, thissupplementary male die, which is of a contour suitable for producingdouble bends in a board which is to serve as a light reflector, consistsof a forming shell, preferably of cast metal, in channel form withsmooth exterior forming bottom and side faces 40 and 4| respectively,the latter terminating in inturned flanges 62 extending toward; eachother but stopping at linear points about diametrically opposite theroll l5 with which they may engage. Interiorly the shell bottom is builtup to provide a curved' seat 4'3 conforming toan extended areaof thebending roll along its under side with which it'is engaged. Between thisseat and the two flanges are spaced chambers containing heating elements44 affixed interiorly to the bottom and sides of the shell. By thisarrangement heat from the element 38 within the bending roll may betransmitted therethrough to the central bottom of the shell whose outerbottom portions and sides: are heated directly by the elements 44.

A forming shell of this character may be sus pended from the roll andyet be maintained in fixed engagement therewith as by a plurality.- ofsaddles 45, each having. a reinforcing rib Miland out-turned feet 4'!through which bolts 48': may be extended for screw-threadedconnection'with the shell flanges wherein are formed threaded socketsfor reception of the bolt ends. At a-top point in each saddle is a boss49 through which is a radial bore threaded to receive a screw 50 havinga pointed acting end adapted to engage the bending roll upon its topside. By advancing each screw slightly the associated clamp may beadjusted as required for expansion of the bending roll when heated, thisoperation taking place before the bolts 43 are tightened to draw theshell closely against the under side of the same roll. Also, the ends ofthese bolts form very slight sockets in the top of the roll whereby theytend to remain fixed'in position thereupon. At the ends of thechannel-like shell are placed closure plates 55 (see Fig. 5), amxed inposition as by screws 56 which enter into threaded bosses (not shown)within the shell at the ends thereof, each plate being apertured toreceive a fitting 51 through which pass electrical conductors 58 toconnect with the heating elements 44. In this way the chambered spaceswithin the shell are closed off at the ends so as to retain therein theheat which emanates from the elements when energized.

In operation, work which is laid across a pair of spaced bending bars(with a spring shield intervening) will be doubly bent around theforming shell to assume substantially the permanent form which is shownin Fig. 4. While this operation proceeds, the entire to-be-bent area ofthe work issubjected to heat in a definite amount. This makes for afaster, more dependable and safer operation. In changing from a flat tocurved or other form, the work is protected by the shield from frictionwith the female die, so that its surface is not scratched, marred, ormarked.

I claim:

1'. In a bending machine, the combination of a hollow male die, a pairof Spaced female dies ad.- justable toward and from each other andspaced from the male die a distance sufficient for reception of a boardtherebetween, means for producing relative movement between the male andfemale dies to the extent that the latter may occupy positionsalongopposite sides of the former to bend a board in conformity with theforming surface thereof, heating means extended longitudinallyof themale die centrally of the female dies, a forming shell ofchannel formapplicable to the male die intermediatelyof the female dies and adaptedto occupy a position therebetween, the shell being formed interiorlywith a central seat'conformed to and engaging with the proximatesurfaceof the male die and'with inturned flanges extended'close-to themale die at points remote from theseat and definingtherewithtwo sidechambers open only toward the. male die, heating means: extendedlongitudinally. withinithe twoshell chambers, a, plural-ity'of; saddleslaid over the male die and. extended towardfopposite edges of the shell,screw means connecting-each saddle and the-shell adaptedto-draw and holdthe latter tightly against the former,- and ;screw means extendedthrougheach. saddle at a point opposite the shell engageablewiththe-male die withvariablefriction to hold the. saddle. in aa'fixedposition of adjustment thereupon.v

2. In a bending machine, the combinationofa male die, a pair of spacedfemale dies adjustable toward andfrom each other and spaced-from themale die a distance sufiicient forreception of a board therebetween,meansv for producing relative movement between the-male. and female diesto the extent ,thatthe latter mayoccupypositions along opposite sides.of the former-t0 bend a board in conformity with the formingsurfacethereof, a forming shell applicable to. the male, die intermediately of,thefemale dies-and adapted to occupy av position therebetween, thevshell being formed interiorlywith .a chamber. open only to.- Wardthemale die, heatingrneans-extendedlongitudinally within the shell,chamber. a, plurality ofsaddles laidoverthe maledieand extended toward,opposite. edges of the. shell, andscrew means connectingeach saddle and.theshell adapted to draw and hold, the latter tightly against'theformer.

3. Ina bendingmachine the combinationzofa male die, a pair of spacedfemale dies spaced from the male die a distance sufficient for receptionof a board therebetween, means for producing relative movement betweenthe male and female dies to the extent that the latter may occupypositions along opposite sides of the former to bend a board inconformity with the forming surface thereof, a forming shell applicableto the male die intermediately of the female dies and adapted to occupya position therebetween, a plurality of saddles laid over the male dieand extended toward opposite edges of the shell, and screw meansconnecting each saddle and the shell adapted to draw and hold the lattertightly against the former.

4. In a bending machine, the combination of a male die, a forming shellof contour other than the male die afiixed immovably thereto, a pair ofspaced female dies adjustable toward and from each other and spaced fromthe shell a distance sufficient for reception of a board therebetween,means for producing relative movement between the male and female diesto the extent that the latter may occupy positions along opposite sidesof the shell to bend a board in conformity with the forming surfacethereof, means for heating spaced areas of the shell and other meansindependently thereof for heating the male die in an area between thespaced heated areas of the shell, and means extending between theshelland male die opposite the heated area of the latter for conductingheat to the shell in the unheated area thereof.

OSCAR BERGSTROM.

